Enhancement of protein detection performance in field-effect transistors with polymer residue-free graphene channel

In comparison with mechanically exfoliated graphene (Gr) or chemically driven Gr, the detection of proteins using chemical vapor-deposited (CVD) Gr has been limited due to polymer residues remaining after polymer-mediated transfer of CVD Gr, which hampers the effective immobilization of probe molecules. We attempted to elucidate whether Au-mediated transfer of CVD Gr could facilitate the detection capability of a protein biomarker for cancer by generating a higher-quality Gr surface compared with polymethyl methacrylate (PMMA)-transferred Gr. Au-transferred Gr was investigated using various chemical and electrical analyses, and the results indicated the lack of polymer residue, higher p-doping, and higher channel mobility compared with PMMA-transferred Gr. The cleaner Gr surface of Au-transferred Gr FET significantly enhanced the protein detection sensitivity compared with that of PMMA-transferred Gr FET.